Plastic cards are commonly printed using a suitable printing mechanism in a card processing system. One known plastic card printing mechanism is a retransfer printer. Retransfer printing is a known printing process where an image is printed by a printing mechanism onto an intermediate retransfer material. After the image is printed, the intermediate retransfer material is transferred by lamination onto the surface of the plastic card that is to bear the printed image. Further information on retransfer printing can be found in, for example, U.S. Pat. No. 6,894,710 which is incorporated herein by reference in its entirety. Another known plastic card printing mechanism is a direct-to-card printing mechanism where the printing is applied directly to a surface of the plastic card from a print ribbon.
Most plastic card printing uses CMY printing, not CMYK. Printing black text and barcodes using black dye-printing lacks sufficient density (i.e. darkness), so instead greys are printed using cyan (C), magenta (M), yellow (Y) blended together. Due to limitations of not being able to consistently balance the C, M and Y to produce a neutral grey, these composite greys tend to have shades of cyan, magenta or yellow.